Apparatus for a rigid road which has a textured surface

ABSTRACT

A profile beam having a working surface constituted by alternate ridges and grooves is drawn, while being vibrated and whilst while to the application of a uniform downwardly directed force, across the surface of cement which has been laid to form a road, airplane runway or the like and which is still plastic, whereby parallel grooves are formed in said cement by the ridges. The grooves, which constitute the texture applied to the road surface, may extend at right angles to the traffic flow direction and will in that case be parallel to one another throughout or may make an angle of less than 90* with the traffic flow direction.

United States Patent [191 Maynard et a1.

[ Reissued Aug. 19, 1975 APPARATUS FOR A RIGID ROAD WHICH HAS A TEXTUREDSURFACE [73] Assignee: The Cement and Concrete Association TerminalHouse, London, England [22] Filed: Apr. 12, 1974 [21] Appl. No.: 460,476

Related US. Patent Documents 2,244,742 6/1941 Tyson 299/1 2,261,76611/1941 Jackson 404/114 2,643,595 6/1953 Jackson 404/113 3,377,9324/1968 Atkinson 404/51 3,516,339 6/1970 Perkins..... 404/75 3,516,3406/1970 Perkins 404/75 3,801,211 4/1974 Perkins 404/75 PrimaryExaminer-Nile C. Byers, Jr. Attorney, Agent, or Fi rmBerman, Bishoff &Platt [57] ABSTRACT A profile beam having a working surface constitutedby alternate ridges and grooves is drawn, while being vibrated andwhilst while to the application of a uniform downwardly directed force,across the surface of cement which has been laid to form a road,airplane runway or the like and which is still plastic, whereby parallelgrooves are formed in said cement by the ridges. The grooves, whichconstitute the texture applied to the road surface, may extend at rightangles to the traffic flow direction and will in that case be parallelto one another throughout or may make an angle of less than 90 with thetraffic flow direction.

14 Claims, 6 Drawing Figures Reiasued Aug. 19, 1975 6 Sheets-Sheet 1DAV/D PAYNE MAYNARD, JOHN IVE/I 1/52 ATTOK VE 7S.

Reissuec? Aug. 19, 1975 s Sheets-Sheet 3 0 N M W57 4 T M z R M; Z W P 0M2 W Reissued Aug. 19, 1975 6 Sheets-Sheet 4 J0 WEA [/ER 5y M 25 gamma)MM 5 kgissu dlu 19, 1915 6 Sheets-Sheet 6 APPARATUS FOR A RIGID ROADWHICH HAS A TEXTURED SURFACE Matter enclosed in heavy brackets 1 appearsin the original patent but forms no part of this reissue specification;matter printed in italics indicates the additions made by reissue.

This invention relates to a method of and apparatus for making pavementsfor roads, runways and similar sites which have textured surfaces.

Texturing of the surfaces of rigid roads has been carried out for agreat number of years by brushing the surface of the concrete withhorse-hair, bass or steel tape bristled brooms before the concrete hashardened. Such brushing has the effect of roughening what mightotherwise be too smooth a surface.

It is now known from field tests which have been made in the UnitedKingdom by the Association with the co-operation of the United KingdomMinistry of Transport. the Road Research Laboratory in the UnitedKingdom and the Country Council of Hertford shire, England that certainpatterns or dispositions of grooves formed in the surface of a wornrigid road markedly improve the skidding resistance of that surface.Thus, wide grooves in such a surface which are parallel to one anotherand which extend transversely will respect to the general direction offlow of the traffic (hereinafter referred to as the traffic flowdirection" in the interests of brevity) have been found to give goodresults, as also have parallel grooves in two sets of which the groovesof one set cross those of the other set, each groove making an angle ofsubstantially 45 with a line which is parallel to the traffic flowdirection.

One method of formation of these grooves in the worn surfaces ofexisting rigid roads is to cut said grooves therein using poweredmachinery having diamond-impregnated steel blades. Other methods haveinvolved the use of machinery which has included cutting heads whichcomprise silicon carbide blades or flails attached to drums which arerotated about horizontal axes. While such methods may well be the onlyfeasible methods by means of which worn surfaces of rigid roads can bere-textured in order to avoid the expense of and the traffic dislocationcaused by removal of the worn pavement and the laying of new concretepavement, it is considered to be undesirable to texture in such alaborious and expensive manner the surface of any road which is eithernew or being repaved.

The principal objects of the present invention are to provide a methodof texturing the surface of a rigid road and an apparatus operable tocarry said method into effect, said method being free from orsubstantially free from the disadvantages mentioned.

Accordingly, from one aspect, the present invention consists in a methodof making a textured-surface rigid road, which method includes thefollowing steps, namely, floating a vibrating groove-forming profilebeam across the surface of concrete which has been laid to the depthrequired for the finished road and which is still in a plastic state inorder to form at least one groove at a time in the surface of saidplastic concrete and thereafter permitting or causing said concrete toharden, whereby a rigid road having a textured surface is formed.

ln one embodiment of said method, said beam is floated across saidconcrete in a first direction of traverse to form said one groove or setof grooves in said surface and is then moved in a direction which isparallel or substantially parallel to the traffic flow direction beforebeing floated in a second direction of traverse opposite to said firstdirection of traverse to form another groove or set of grooves in saidsurface.

The angle which each of said first and second directions of traversemakes with the traffic flow direction may be widely varied to form atextured surface in accordance with the specification laid down by theauthority concerned. Thus, said first and second directions of traversemay be normal to said traffic flow direction, the grooves formed beingparallel to one another and such as can be formed by a single profilebeam. Alternatively, each of two profile beams spaced apart from oneanother along said trafiic flow direction may be floated across saidconcrete surface in said first and second directions of traverse, thedirections of traverse of one of said profile beams crossing thedirections of traverse of the other of said profile beams symmetricallyor asymmetrically with respect to said traffic flow direction.

It is thought at present that the concrete should be allowed to standfor a period of time after the instant of finishing the surface by theconcrete paving machine before the profile beam or either of the profilebeams is floated across said surface to form said groove or set ofgrooves therein. This standing period will be governed to some extent bythe water content of the concrete mix, its workability and its rate ofsetting, which is determined to a large extent by the type of cement andambient conditions and will also be governed by the length of the trainconstituting the pavement laying machine. A typical train consists of aspreader, a leveller, a compacting machine, and a finishing machine. Anapparatus capable of carrying the method according to the presentinvention into effect will come after the finishing machine and thiswill mean, in general, a lapse of time of, say, 45 minutes between thespreading and surface-texturing operations.

Said methods may include the further step of cleaning the workingsurface of said profile beam after a predetermined number of traverseshave been made thereby. Preferably, cleaning will be effected only aftercompletion by the profile beam of movement in one of said first andsecond directions of traverse.

From another aspect, the present invention consists in apparatusoperable to carry into effect said method of making a textured-surfacerigid road, said apparatus including a profile beam which has agroove-forming working surface and a carriage which is movable upon asupporting gantry which is in turn movable along the traffic flowdirection, said profile beam being operatively connected to a vibratorand being adjustably suspended from said carriage, the arrangement beingsuch that, if said gantry were to be so positioned as to span a surfaceof concrete which has been laid to the depth required for the finishedroad and which is still in a plastic state and if said working surfaceof the profile beam were to be placed in contact with the surface ofsaid concrete and if said carriage were to be moved upon said supportinggantry while said profile beam was being vibrated by said vibrator. theworking surface of the profile beam would be floated across the surfaceof said concrete and would form therein at least one groove, the mannerof suspension of said profile beam not only being such that whatevereffective load were predetermined by adjustment thereof before saidmovement of the carriage would be applied to said plastic concrete whilesaid working surface and the surface of said plastic concrete were inmutual contact but also being such that the moving profile beam wouldassume an attitude in which the leading edge thereof would be higherthan the trailing edge thereof in relation to the plane containing thesurface of the plastic concrete before the formation therein of anygroove.

In the preferred embodiment of said apparatus, said profile beam issuspended upon constant force spring means; such means could beconstituted by a number of Tensaton springs. Tensator" is a trademarkutilized by Tensator Ltd, a British manufacturer located in NewportPagnell, Bucks County, England. The partieular Tensator" springsdisclosed in the drawing of this application are ribbons of speciallytreated spring material having a coiled portion and a straight portionand which yield substantially constant tensile force no matter how muchof each ribbon is unwound from the coil portion.

Said vibrator is preferably mounted upon said profile beam.

In the preferred embodiment of the apparatus, the working surface ofsaid profile beam consists of downwardly directed parallel ridges whichdefine parallel troughs, those marginal portions of the beam whichextend in directions normal or substantially normal to the parallelridges being canted upwardly towards said gantry so as to reduce theincidence of said marginal portions digging into and ploughing up saidplastic concrete. Said ridges are preferably of square or rectangularsection.

Said profile beam will preferably be made out of a solid block of metalbecause, when said profile beam is constituted by or includes a plate towhich squaresection rods have been fixed in parallel relationship toform the groove-forming ridges, it has been found that there is atendency for particles of said plastic concrete to penetrate betweensaid rods and said plate.

Preferably, cleaning means will be provided on the gantry operable toremove from the working surface of said beam at least the majorproportion (if not all) of any adherent particles of said plasticconcrete in order to prevent any accretion thereof on said workingsurface.

The carriage is, in one embodiment of said apparatus, driven by saidreversible motor through chains and sprockets keyed to transverse shaftscarrying guide wheels whose single circumferential flanges extend into astraight guide slot.

An apparatus according to the present invention could be constructed asa self-contained vehicle intended for power-assisted travel along, forexample, parallel rails either under the control of a driver or operator or under the control of a program-operated device. Alternatively,an apparatus according to the present invention could be constructed asan ancillary part of a concrete paving machine or train, said apparatusbeing connected to such machine or train by means of one or more cables,hawsers or the like which, in conjunction with intermittently butsynchronouslyoperated winches on said apparatus, would enable saidapparatus to follow the paving machine at the requisite spacing topermit the laid concrete to stand for the pcriod of time considered tobe desirable before groove formation in the plastic concrete iseffected.

The present invention will now be more particularly described withreference to the accompanying drawings, in which:

FIG. 1 illustrates in side elevation one embodiment of an apparatusoperable to make a textured-surface rigid road in accordance with themethod of making such a road disclosed herein;

FIG. 2 illustrates said apparatus in top plan view;

FIG. 3 illustrates in end elevation the apparatus shown in FIG. 1, saidelevation being of the left-hand end of the apparatus shown in FIG. 1;and

FIGS. 4, 5 and 6 illustrate detail views on a larger scale than that ofFIGS. 1 to 3, of the traversible and vibratable groove-forming profilebeam which is adjustably suspended in said apparatus and constitutes theessential component of the apparatus, said views representing,respectively, side elevation, 21 top plan, and an end elevation of saidbeam.

The apparatus illustrated in the drawings consists essentially of agantry 10 which is made from box-section steel members 11 appropriatelysecured to one another to form a rigid frame, the gantry being supportedby flanged wheels 12 which are mounted upon the gantry and which areintended to run on rails 13 which would extend alongside the formworkwithin which the concrete to be laid on the subgrade. Some or all ofsaid wheels 12 may be articulated, for example may be castor wheels.

The gantry 10 supports at one end a generating set 14 operable to supplythe electric power necessary to drive a plurality of electric motors.Two electrically driven geared drive units 15 are mounted upon thegantry 10 and are operable to drive the two wheels 12 with which theyare associated, the drive being by way of endless chain 16 and sprocketwheels 17 or some similar arrangement. The two drive units or motors 15are both variable speed and reversible.

An hydraulic power pack 20 includes an electric motor 21, an hydraulicpump 22, a relief valve gauge 23 and a reservoir 24.

An electrically operated geared drive unit 25 is mounted upon a carriage26, the output shaft of the unit have toothed sprockets 27 thereon whichdrive toothed sprockets 28 by way of endless chains 29, the sprockets 28being keyed to parallel axles 30 which are rotatably connected to thecarriage. The axles 30 carry rollers 31 which are in contact with a rail32 and also carry guide wheels 33 which, coacting with parallel guiderails 34 which between them define a rectilinear slit 35, provide guidedtraverse of the carriage 26 which is moved when the motor 25 causes therollers 31 to rotate in contact with the rail 32. The motor 25 isvariable speed and reversible. The carriage 26 carries tripping members36 and limit switches 37 are mounted on one of the guide rails 34.

Connected to the carriage 26 for movement there with is an assemblywhich includes two substantially A- shaped beams 40 which are connectedto one another by a longitudinal beam 41, two double-acting hydrauliccylinders 42 which are mounted upon said beams at the opposite ends ofsaid beam 41 in the vicinities of the beams 40, a profile beam 43, aplurality of constant force springs 44 each of which is connected at 45to the beam 41 and at 46 to the beam 43, the cylinders 42 having stems47 whose free ends are connected to said beam 43 by way of aparallel-motion or scissors linkage 48.

Mounted on the profile beam 43 is an hydraulic motor 50 which isvariable speed and reversible, the output shaft of said motor beingconnected by way of a shaft coupling 51 to a drive shaft 52 which issupported for rotation in two opposite directions of rotation in ajournal box 53. Adjacent the free end of said shaft 52 is ke ed adriving pulley 54 which is drivingly connected by driving belts 55 to adriven pulley 56 which is keyed to a vibrating shaft 57, said shaft 57being supported by and running in pillow block bearings 58 which arecarried by the profile beam 43. Keyed to the shaft 57 are spacedeccentrically mounted masses 59 which, when the shaft 57 is rotated bythe drive from the motor 50, will cause the entire profile beam tovibrate.

The profile beam 43 is connected to the lower and free ends of the twobeams 40 by guide chains 60.

The gantry also supports a control console 65 into which are brought allelectrical and hydraulic lines, whereby the operation of the apparatuscan be conveniently controlled.

The operation of the apparatus is considered to be self-evident and itwill, therefore, suffice to point out that the working surface 70 of theprofile beam 43, consisting of alternate parallel ridges and troughs,will form parallel grooves in the plastic concrete when the carriage 26is caused to traverse the formation by riding along the rails 32, 34,the formation of said grooves being assisted by the vibration producedby rotation of the shaft 57 to which the eccentric masses 59 are keyed.At the end of each traverse, the profile beam 43 is lifted out ofcontact with the concrete by appropriate operation of the hydraulicactuators 42, said beam 43 thereafter being lowered again under thecontrol of said hydraulic actuators into contact with the concrete afterthe gantry 10 has been moved in the requisite direction along the rails13 by the powered wheels 12, whereupon the carriage 26 is caused totraverse the formation in the opposite direction of travel thereof tothat previously effected. The limit switches 37 are tripped by themembers 36 to stop the respective traverse of the carriage and also tostop the hydraulic motor 50.

The profile beam is lowered by means of the hydraulic pistons onto thesurface of the concrete pavement in which position the scissors linkagesrelease any load carried by the pistons. The profile beam floats on thesurface of the concrete with part of the mass of the beam supported bythe constant force or Tensator" springs. The proportion of the masscarried by the springs obviously may be controlled by selecting a springor springs having the desired tension characteristics or by adding orsubtracting springs, to accommo date variations in the consistency ofthe concrete. Variations in the consistency of the concrete can also beaccommodated by changes in the frequency of the applied vibration, whichfluidizes the concrete and the speed of traverse of the profile beam.

Again, the wheels 12 which are shown as being powered by the motors inthe drawings need not be so powered because the apparatus could form theterminal part of a train of pavement-laying machinery, being connectedthereto by cables, hawsers or the like, which (in conjunction withintermittently-operated but synchronously-operated winches) would enablethe apparatus to follow the preceding constituent elements of saidmachine at the end of each traverse of the carriage 26.

If cleaning means operable to keep the working surface of the profilebeam 43 are provided (for example brushes, pressurized fluid jets and soon, possibly in combination with one another), it would be desirable toextend the gantry 10 to an extent sufficient to ensure that any adherentmaterial on said working surface would not fall on the surface of theconcrete which has been or which is to be textured. Thus, the gantry 10might be lengthened to the right as seen in FIG. 1 and cleaning would beeffected at the end of alternate traverses.

The parallel ridges and troughs constituting said working surface arepreferably formed by working a solid block or plate; The creation ofsaid ridges by securing parallel square-section rods to a plate islikely to give rise to trouble because there is a tendency for particlesof the plastic concrete to penetrate between the rods and the plate.These particles become impossible to remove on site and lead to bucklingor deformation of the rods, said buckling or deformation giving rise tovariations in depth of groove in the concrete.

As will be seen best in FIGS. 1 and 6, the leading/- trailing edges ofthe beam 43 are located above the surface of the plastic concrete. Thiscanting upwardly of the relevant portions of said beam 43 is for thepurpose of reducing the incidence of the beam 43 digging into andploughing upsaid concrete. The guide chains 60 also assist in thispreventive action.

Switches other than the limit switches 37 may be provided in order, forexample, to actuate the cleaning means if cleaning means are providedand/or to control the operation of said winches. The switches may betime-controlled or remotely controlled from a part of thepavement-laying machine.

A swinging arm boom is provided in order that all of the hydraulic lines(not illustrated) may be bundled and maintained in a position in whichthey will not foul and be damaged by the traversing carriage.

What 1 claim as my invention and desire to secure by Letters Patent ofthe United States is:

1. Apparatus for making a textured-surface rigid road of concrete or thelike, comprising a gantry adapted to span at least a portion of a newlylaid plastic concrete road, means supporting said gantry on a subgrade,a frame movably supported on said gantry, a profile beam having agroove-forming working surface suspended by tension springs from saidframe, said grooveforming surface having rib means extending in thedirection of movement of said frame and suspended profile beam, pistonmeans between said frame and said profile beam for raising and loweringsaid beam relative to the frame, a flexible connection between saidpiston means and said profile beam, and vibrator means directlyconnected to said profile beam, whereby upon actuation of said vibratormeans the profile beam fluidizes the underlying concrete and molds atleast one groove therein while being floatingly supported by saidtension springs.

2. An apparatus as claimed in claim 1, wherein said tension springs aresubstantially constant force springs which floatingly support saidprofile beam from the frame.

3. An apparatus as claimed in claim 1, wherein said vibrator is mountedupon said profile beam.

4. An apparatus as claimed in claim 1, wherein said flexible connectionbetween said piston and said profile beam comprises a set of linkspivoted to each other at their ends and forming a parallelogram.

5. An apparatus according to claim 1, wherein said frame comprises apair of parallel Ashaped members spaced from one another, said profilebeam being suspended between said A-shaped members by said tensionsprings, piston means and flexible connection, and by flexible elementsconnecting said profile beam to the legs of said A-shaped members.

6. An apparatus as claimed in claim 1, wherein said frame is supportedby a carriage movable on said gantry, and wherein a reversible motor isprovided to drive said carriage at constant or varied speeds.

7. An apparatus as claimed in claim 6, wherein limit switches areprovided which are tripped by the carriage when the carriage reaches theend of a respective traverse of the gantry, said limit switches beingoperative to stop said carriage and said vibrator means at the end of atraverse of the gantry.

8. Apparatus as claimed in claim 6, wherein said carriage is driven bysaid reversible motor through chains and sprockets keyed to transverseshafts carrying guide wheels whose single circumferential flanges extendinto a straight guide slot.

9. Apparatus as claimed in claim 1, wherein the working surface of saidprofile beam consists of downwardly directed parallel ridges whichbetween them define parallel troughs. those marginal portions of thebeam which extend in directions substantially normal to the parallelridges being canted upwardly towards said gantry so as to reduce theincidence of said marginal portions digging into and ploughing up saidplastic concretev (iii 10. Apparatus as claimed in claim 9, wherein saidridges are of rectangular section.

11. Apparatus as claimed in claim 9, wherein at least that part of saidprofile beam which provides said working surface thereof is made out ofa solid block of metal.

12. Apparatus as claimed in claim 1, including wheels on said gantry,power means operable to effect power assisted travel of said apparatusin each of two altemative, opposite directions of travel.

13. Apparatus for making a textured surface rigid road of concrete orthe like, comprising a gantry adapted to span at least a portion of anewly laid plastic concrete road, means supporting said gantry on asubgrade, a frame movobly supported on said gantry for movement alongsaid gantry, a profile beam which has a grooveforming working surfaceand which is floatingly suspended by springs from said frame, saidgroove-formin g surface having rib means extending in the direction ofmovement of said frame and suspended profile beam, means for raising andlowering said beam relative to the subgrade, a flexible connectionbetween said frame and said profile beam, and vibrator means directlyconnected to said profile beam, whereby upon actuation of said vibratormeans when the groove-forming surface of said profile beam is in contactwith said plastic concrete the profile beam fluidizes the underlyingconcrete and moulds at least one groove therein while being floating/ysupported by said springs.

l 4. Apparatus for making a textured surface rigid road of concrete orthe like as claimed in claim 13, wherein said springs which floating/ysuspend the profile beam are tension springs.

1. Apparatus for making a textured-surface rigid road of concrete or thelike, comprising a gantry adapted to span at least a portion of a newlylaid plastic concrete road, means supporting said gantry on a subgrade,a frame movably supported on said gantry, a profile beam having agroove-forming working surface suspended by tension springs from saidframe, said groove-forming surface having rib means extending in thedirection of movement of said frame and suspended profile beam, pistonmeans between said frame and said profile beam for raising and loweringsaid beam relative to the frame, a flexible connection between saidpiston means and said profile beam, and vibrator means directlyconnected to said profile beam, whereby upon actuation of said vibratormeans the profile beam fluidizes the underlying concrete and molds atleast one groove therein while being floatingly supported by saidtension springs.
 2. An apparatus as claimed in claim 1, wherein saidtension springs are substantially constant force springs whichfloatingly support said profile beam from the frame.
 3. An apparatus asclaimed in claim 1, wherein said vibrator is mounted upon said profilebeam.
 4. An apparatus as claimed in claim 1, wherein said flexibleconnection between said piston and said profile beam comprises a set oflinks pivoted to each other at their ends and forming a parallelogram.5. An apparatus according to claim 1, wherein said frame comprises apair of parallel A-shaped members spaced from one another, said profilebeam being suspended between said A-shaped members by said tensionsprings, piston means and flexible connection, and by flexible elementsconnecting said profile beam to the legs of said A-shaped members.
 6. Anapparatus as claimed in claim 1, wherein said frame is supported by acarriage movable on said gantry, and wherein a reversible motor isprovided to drive said carriage at constant or varied speeds.
 7. Anapparatus as claimed in claim 6, wherein limit switches are providedwhich are tripped by the carriage when the carriage reaches the end of arespective traverse of the gantry, said limit switches being operativeto stop said carriage and said vibrator means at the end of a traverseof the gantry.
 8. Apparatus as claimed in claim 6, wherein said carriageis driven by said reversible motor through chains and sprockets keyed totransverse shafts carrying guide wheels whose single circumferentialflanges extend into a straight guide slot.
 9. Apparatus as claimed inclaim 1, wherein the working surface of said profile beam consists ofdownwardly directed parallel ridges which between them define paralleltroughs, those marginal portions of the beam which extend in directionssubstantially normal to the parallel ridges being canted upwardlytowards said gantry so as to reduce the incidence of said marginalportions digging into and ploughing up said plastic concrete. 10.Apparatus as claimed in claim 9, wherein said ridges are of rectangularsection.
 11. Apparatus as claimed in claim 9, wherein at least that partof said profile beam which provides said working surface thereof is madeout of a solid block of metal.
 12. Apparatus as claimed in claim 1,including wheels on said gantry, power means operable to effectpower-assisted travel of said apparatus in each of two alternative,opposite directions of travel.
 13. Apparatus for making a texturedsurface rigid road of concrete or the like, comprising a gantry adaptedto span at least a portion of a newly laid plastic concrete road, meanssupporting said gantry on a subgrAde, a frame movably supported on saidgantry for movement along said gantry, a profile beam which has agroove-forming working surface and which is floatingly suspended bysprings from said frame, said groove-forming surface having rib meansextending in the direction of movement of said frame and suspendedprofile beam, means for raising and lowering said beam relative to thesubgrade, a flexible connection between said frame and said profilebeam, and vibrator means directly connected to said profile beam,whereby upon actuation of said vibrator means when the groove-formingsurface of said profile beam is in contact with said plastic concretethe profile beam fluidizes the underlying concrete and moulds at leastone groove therein while being floatingly supported by said springs. 14.Apparatus for making a textured surface rigid road of concrete or thelike, as claimed in claim 13, wherein said springs which floatinglysuspend the profile beam are tension springs.